I have a problem with my Pentax K100d that I would be gratful if\nanyone could\noffer any advice on.\n\nThe problem is that in any mode requiring auto exposure, the camera\nmassivly underexposes to the extent where output is just black. For\nexample, in low light conditions where I would expect shutter speeds\nof say 1/20 or slower, it is selecting 1/500 - 1/2000. Intermittently\nhowever it works correctly. Manual exposure works fine.\n\nThis occurred a while ago and it was sent back to pentax who seemed to\nfix the problem (albeit they kept the thing for 2 months). The\nservice docket said something like exposure reset or re-calibrated.\nAfter that things were ok again for a while but the problem has\nstarted again.\n\nThe camera is still under warrantee (just) and so I intend to send it\nback again but my concern is that pentax will do a temporary fix again\nbut that the camera has a more serious fault somewhere. Can anyone\nsuggest what the problem might be? Should I be insisting on a\nreplacement? Can the exposure be user reset/re-calibrated? many\nthanks for any thoughts or suggestions.